This section contain separate instructions for a standard upgrade procedure and for a simplified upgrade.
9.0 does not support downgrade or rollback after upgrading to 9.0, so it is especially important to make a full backup of both configurations, database, and runtime data as described in the Standard Upgrade procedure.
The Standard upgrade procedure should be used when it is required to minimize downtime during upgrade and to ensure that configurations, persisted data (in the file system or database), and system properties are properly migrated. The Standard upgrade procedure needs to be done step-wise via every minor and major.
The Simplified Upgrade procedure should be used when this is not required, and you only wish to migrate configuration data. The Simplified upgrade procedure can be done over multiple majors and minors in one upgrade.